If you are doing this for the challenge, by all means, do the rebuild. The GM ZZ4 crate engine with run around $3800 plus sales tax. This is hard to beat when adding the cost of your parts, machine work and personal time involved. This engine also has a 2/24 warranty as well

If you will rebuild regardless, this is the parts breakdown on how GM gets 355 HP. Good luck.

ZZ4 Technical Information

Horsepower 355 @ 5250 RPM
Torque 405 @ 3500 RPM
Max. Recommended RPM 5800
Compression Ratio 10:1
Block 10105123 Four bolt main, cast iron
Crankshaft 12556307 Forged steel
Connecting Rods 10108688 PM rods
Pistons 10159436 High Silicon aluminum with offset pins
Piston Rings 12528817
Camshaft 10185071 Hydraulic roller
Lift .47" I, .510" E.
Duration @ .050: 208º I, .221º E.
Intake Manifold 10185063 aluminum dual plane
Distributor 1104067 HEI
Cylinder Heads 12556463 Aluminum 58cc combustion chambers
Intake Valves 10168465 1.94"
Exhaust Valves 10168514 1.50"
Valve Springs 12551483 LT4 chrome silicon
Rocker Arms 10089648 1.5 ratio
Valve Lash Zero
Spark Plugs FR5LS Gap .035
RapidFire #5 Gap .045
Fuel 92 Octane
Ignition Timing 10 BTDC @ 4000 RPM
32º total @4000 RPM with vacuum advance disconnected

Technical Notes: Carburetor, spark plug wires, starter, oil filter and oil filter adapter, and exhaust manifolds not included. Distributor P/N 1104067 or melonized distributor gear P/N 10456413 must be used on all crate engines with steel camshafts.



Customize your ZZ4 with GM Performance Parts
Below is a sample of the parts that you'll find throughout our catalog to help you complete your crate engine installation or customize your crate engine for your specific application.
12361146 High torque Mini Starter High Power, compact design.
Technical Note: This starter is not recommended for competition.
12361056 GM Performance Parts Logo 8mm Spark Plug Wires
12342079 Chrome 14" High Performance Air Cleaner
24502586 HOT Cam-Hydraulic steel roller designed for showroom stock racing
12370839 1.6 Ratio Roller Rocker Arms Required with HOT cam
24502540 Valve Cover Adapters - Allows use of flange mount valve covers on center bolt style heads - Required when roller rocker arms are used